This invention relates to a sealing device in a mailing machine and more particularly relates to a sealing device which also deskews misaligned mailpieces being processed through the mailing machine.
Mailing machines which process pieces of mail (such as envelopes) through a plurality of processing stations are well known and embodied, for example, in U.S. Pat. No. 5,098,734 which issued to O'Dea, et al. on Mar. 24, 1992. These mailing machines typically singulate and transport individual envelopes through an envelope flap moistener, a flap sealing device, and a postage meter where printing of postage on the envelope occurs. Most postage meters utilize a rotary drum with a die thereon or a flatbed type of die for printing the postage on the envelope. The inks used in these postage meters are oil-based inks which are very stable in water. Therefore, if the surface of the envelope being printed on becomes wet due to excess moistening fluid which has been deposited thereon by the sealing device, the printed postage will still be satisfactorily printed onto the envelope.
Currently, because of environmental concerns, the use of water based inks in postage meters is highly desirable. Moreover, because of the flexibility in printing provided by digital printing devices, there is a trend to incorporate digital printers utilizing ink jet printing technology in postage meters for the purpose of printing the postal indicia and an optional advertising slogan on the envelope. One of the more common ink jet printers incorporates bubble jet printing technology which requires the utilization of a water-based ink in order to operate. However, since the very nature of a water-based ink is that it is soluble in water, a problem exists in that if any water is present on the print surface of the envelope. That is, the image which is printed by a bubble jet printer on the moistened envelope will be smeared and of a degraded quality because the water based ink will react and begin to dissolve in the water which is present on the envelope print surface.
Another important aspect of ink jet printers is that the surface of the item which is printed on must be registered a fixed distance from the nozzles of the ink jet printer in order to achieve good quality printing. In U.S. Pat. Nos. 5,740,728 and 5,813,327, which are hereby incorporated by reference, an endless belt is used to transport and register the mailpieces against the bottom side of a transport deck. The printer is positioned a fixed distance from the deck and prints onto the mailpiece through an opening in the deck. Accordingly, since the endless belt registers the mailpiece against the underside of the deck and the printer is positioned a fixed distance from the deck, the desired gap between the printer and the printing surface of the mailpiece is accurately maintained.
However, the above described endless belt transport device requires that the endless belt be positioned away from a rear mailpiece registration wall. This allows the mailpiece to pass under the printer and to provide room for a mailpiece flap folding skin which folds the mailpiece flap against the mailpiece body prior to its passing between a roller flap sealing assembly. The endless transport belt acts on the outboard side of the mailpiece and passes around backup rollers which cooperate with spring biased idler rollers to jointly transport the mailpiece. However, due to the space constraints required for the flap ski, when small mailpieces (i.e. 51/8 inches long) are being transported they will only be in a single backup roller/idler roller nip for a short distance prior to entering into the sealing roller nip. During this period of time, the registration wall and the flap folding ski create drag on the inboard side of the mailpiece while the outboard side is being driven by the endless belt assembly. The drag causes a torque to be created on the mailpiece that moves the trailing edge away from the registration wall while placing the mailpiece in a skewed orientation relative to the registration wall. The mailpiece then continues to be transported in a skewed orientation through the mailing machine to the printer so that a postage indicia is printed in a skewed orientation relative to the top of the mailpiece.
Thus, what is needed is a sealing device which seals the envelope flap of a mailpiece being transported in a skewed alignment and concurrently deskews the misaligned mailpiece.